Electrical turning gear for starting internal-combustion engines



Nov. 18, 1930.

F. H. ROYCE 1,782,318

ELECTRICAL TURNING GEAR FOR STARTING INTERNAL COMBUSTION ENGINES Filed Jan. 16, 1929 n INVENTOR. twmyglfiw By M ATTORNEYf Eatented Nov. 18, 1930 UNETED STATES PATENT GFFICE FREDERICK HENRY BOYCE, OF WEST WITTERING, NEAR CHICI-IESTER, ENGLAND, AS-

SIGNOR TO ROLLS ROYCE LIMITED, OF DEE-BY, ENGLAND ELECTRICAL TURNING GEAR- FOR- STARTING INTERNAL-COMBUSTION ENGINES Application filed January 16, 1929, Serial No. 332,970, and in Great Britain February 14, 1928.

This invention has reference to electric turning gear for starting internal combustion engines, of the type in which a pinion fixed for rotation on an extension of the armature shaft of the starting motor, is caused to more axially into engagement with a toothed wheel geared to the engine shaft.

in turning gear of the type referred to as heretofore made, the pinion has been arranged in its normal (i. e, out of engagement) position either more remote from, or nearer to, the motor than the toothed wheel with which it engages.

The latter arrangement is often desirable to meet the exigencies of design of the engine, but has a comparative disadvantage, in that the over-hang or extended part of the shaft beyond its adjacent hearing, is at its maximum when the instrument is Working, thus throwing a great bending strain on the shaft and heavily loading the hearings.

T he object of this invention is to eliminate or minimize this disadvantageand to make other constructional improvements.

According to this invention the relative diameter of the shaft, and the bearing in the end boss of the motor casing adjacent the pinion on the one hand, and of the pinion on the other hand, are such that the pinion (following the axial movement of the shaft) can be made to recede (when in its normal position) into the hollow of the hearing.

An example of this invention is illustrated in the accompanying drawings.

Fig. 1 shows a sectional elevation of the starter motor, and Fig. 2 a. portion of Fig. 1, to an enlarged scale.

a is a bracket forming part of the engine crankshaftcase, 0 the case containing the starter connected to such bracket, a an end cover of the case of the starter, a a flanged sleeve and a a bearing bush, 6 are poles of the starter motor, 6 the field windings, b is the armature and b the commutator, 0 is the shaft of the motor having an enlarged part a rotating in the hearing bush a and o is the pinion ri idly mounted on the shaft (for rotation) of the smaller diameter than the enlarged part 0 cl is the fly wheel of the engine.

vVith apparatus as described the fly-wheel can be arranged in close proximity to the end of the motor and when the pinion is engaged therewith such pinion is in close proximity to the adjacent hearing of the shaft.

lVhat I claim is 1. Electric turning gear for starting internal combustion engines of the type in which a pinion fined for rotation on an extension of the armature shaft of a starting motor is FREDERICK HENRY ROYCE. 

